This application is based on Japanese Patent Application No. 2002-70298, filed on Mar. 14, 2002, the entire contents of which are incorporated herein by reference.
A) Field of the Invention
The present invention relates to a lamination structure with copper wiring and its manufacture method, and more particularly to a method which is suitable for manufacturing semiconductor devices and includes a process of forming a copper wiring layer by a damascene method, and to a lamination structure having a conductive member such as copper embedded in a film made of an insulating material which contains fluorine.
B) Description of the Related Art
Demands for high performance and high speed of semiconductor devices require to shorten a delay time of an electric signal transmitting in a wiring layer. One approach to shortening a delay time is a lowered dielectric constant of an interlayer insulating film. If fluorine is doped in an interlayer insulating film, the dielectric constant can be lowered.
However, if fluorine is doped in an interlayer insulating film, peeling off is likely to occur at the interface of the interlayer insulating film when the film is laminated. JP-A-HEI-11-8235 discloses techniques of preventing peeling off by doping nitrogen into an interlayer insulating film doped with fluorine.
Even if nitrogen is doped in a fluorine-doped interlayer insulating film, local peeling off occurs in some cases.
An object of this invention is to provide a lamination structure having a fluorine-doped interlayer insulating film in which lamination structure peeling off is difficult to occur, and its manufacture method.
According to one aspect of the present invention, there is provided a method of manufacturing a lamination structure, comprising: (a) a step of exposing a surface of a substrate to hydrogen plasma to clean the surface, a partial area of the surface exposing an insulating material containing fluorine and at least a partial area in the other area of the surface exposing a conductive material containing copper as a main composition; and (b) a step of forming a first film made of an insulating material on the cleaned surface.
By exposing the surface of a conductive member to hydrogen plasma, fluorine atoms in the surface layer can be efficiently removed. Removal of fluorine atoms promotes adhesion of the first film on the surface of the conductive member and the first film can be prevented from being peeled off.
According to another aspect of the invention, there is provided a lamination structure comprising: a first insulating film made of fluorine-containing insulating material; a conductive member filled in a recess formed through the first insulating film, the conductive member containing copper as a main composition; and a second insulating film made of insulating material and disposed on surfaces of the first insulating film and the conductive member, wherein a fluorine density on an upper surface of the conductive member is 10 atom % or lower.
By setting the fluorine density on the upper surface of the conductive member to 10 atom % or lower, adhesion of the second film on the conductive member can be promoted and the second film can be prevented from being peeled off.